Mayor Bloomberg raced to champion the First Amendment this week amid debate over an anti-Israel forum at Brooklyn College — and never mind that free-speech rights weren’t being threatened in the least.

The school’s political-science department had decided to sponsor speakers from the “BDS” movement — which aims to punish Israel with boycotts, divestment and sanctions. At issue was not speech rights or academic freedom, but the propriety of a scholarly institution hosting a hate-filled, intellectually dishonest slam-fest of a key democratic, peace-seeking US ally.

On the taxpayers’ dime.

Since no one disputed the sponsors’ rights, Mike no doubt figured it would be safe — noble-seeming, even — to defend them. And anyone who criticized the event should take his opinions to Pyongyang.

“If you want to go to a university where the government decides what kind of subjects are fit for discussion, I suggest you apply to a school in North Korea,” he said.

That’s about an 8.3 on the Bloomberg piety scale. A BDS speaker went further, warning of “the rise of a new McCarthyism” — that is, fretting over the fate of brave souls who dare to utter left-wing “truths” on a college campus. Some imagination, huh?

Suppose the school can host forums for one-sided debates (some pro-Israel students said it was hard to voice dissent). That wouldn’t make it right — especially when taxpayer dollars are footing the bill.

Typical Mike, though: He played the same game during the fight over the Ground Zero mosque. Back then, he was downright teary-eyed as he dressed up his politically correct arguments in the holy garb of religious freedom. Anyone who disagreed was a bigot — and never mind that many Americans found the mosque’s proximity to Ground Zero, where Islamists killed 3,000 folks, disconcerting.

(Actually, the plan may have been less about sticking a thumb in America’s eye than simple self-enrichment: Its former imam is now accused in a lawsuit of stealing from religious nonprofits he founded.)

Straw men topple easily. In an honest debate, the mayor would have to acknowledge that other citizens can legitimately disagree with him. After all, New York isn’t North Korea.